Hi All.
I thought about writing this thread as I am often making things, and whilst I am practical I am constantly blown away by the knowledge of the 'practical' types of the generation senior to me.
I intend to keep this thread as concise as possible, and it was somewhat inspired by a recent thread posted about panel drilling and broken drills.
Question:
I often drill aluminium cases, sometimes 10mm Copper or Aluminium plate, up to perhaps 1/2".
The single largest issue I find is binding of aluminium swarf onto the tool face, be that jobber drill, carbide mill, file, cone/step drill.
What lubrication, or methods can I use to keep clean/clean off the tools?
Will the right cutting agent prevent this binding of Aluminium to the tool?
I mean...in all honesty, I prefer trying to work Copper 🤣
I thought about writing this thread as I am often making things, and whilst I am practical I am constantly blown away by the knowledge of the 'practical' types of the generation senior to me.
I intend to keep this thread as concise as possible, and it was somewhat inspired by a recent thread posted about panel drilling and broken drills.
Question:
I often drill aluminium cases, sometimes 10mm Copper or Aluminium plate, up to perhaps 1/2".
The single largest issue I find is binding of aluminium swarf onto the tool face, be that jobber drill, carbide mill, file, cone/step drill.
What lubrication, or methods can I use to keep clean/clean off the tools?
Will the right cutting agent prevent this binding of Aluminium to the tool?
I mean...in all honesty, I prefer trying to work Copper 🤣
The simple rules of metal cutting are:
1) Sharp tools
2) Use cutting fluid
3) Obey the "Feeds and Speeds"
To avoid the problems drilling aluminum, lower the drill rpm, feed slower, and of course use #1 & #2. And, the bigger the bit, the slower you need to go. Aluminum is prone to binding due to its low meting point of 660c (vs 1080c for copper).
1) Sharp tools
2) Use cutting fluid
3) Obey the "Feeds and Speeds"
To avoid the problems drilling aluminum, lower the drill rpm, feed slower, and of course use #1 & #2. And, the bigger the bit, the slower you need to go. Aluminum is prone to binding due to its low meting point of 660c (vs 1080c for copper).
Well at the risk of sounding ungrateful...
Not exactly helpful.
1. Brand new drills so yes...sharp.
2. Cutting Oil is used.
3. Speed probably less than 200rpm since slow speed on my cordless hand drill. Drill press I can change speed but it's probably also less than 200rpm. Pecking works great most of the time, but never seems to work with Aluminium (unless countersinking or something at less than 100rpm)
Not sure how I measure feed rate, other than by my crudely calibrated eye...
Still I have to carefully remove aluminium from the leading edge, whether I try and feed fast or slow.
Maybe an emulsion is better than oil, for cutting aluminium?
my aside point of preferring to work copper, is a little joke, as copper is bad enough
Not exactly helpful.
1. Brand new drills so yes...sharp.
2. Cutting Oil is used.
3. Speed probably less than 200rpm since slow speed on my cordless hand drill. Drill press I can change speed but it's probably also less than 200rpm. Pecking works great most of the time, but never seems to work with Aluminium (unless countersinking or something at less than 100rpm)
Not sure how I measure feed rate, other than by my crudely calibrated eye...
Still I have to carefully remove aluminium from the leading edge, whether I try and feed fast or slow.
Maybe an emulsion is better than oil, for cutting aluminium?
my aside point of preferring to work copper, is a little joke, as copper is bad enough
Are you clamping your work down?
For a home shop use bright high speed steel, grade doesn't matter, M2 is fine. Black oxide will work but is not as good bright at resisting falling. Carbide isn't worth it for hobby use, but if you are so inclined get a coating that is specific to aluminium. Al is very ductile and that is why it galls.
Al loves to be wet, water based coolant is great. Oils will work too, WD-40, tapping oil cutting oil, etc all will work.
You just about can't go too fast in aluminium, but use an RPM that you are comfortable with. Get a squirt bottle with WD-40 and use it to clear your chips when you peck. You can use an acid brush and a can of oil too, when you retract your tool use a wet brush and wipe the chips off.
Good luck.
For a home shop use bright high speed steel, grade doesn't matter, M2 is fine. Black oxide will work but is not as good bright at resisting falling. Carbide isn't worth it for hobby use, but if you are so inclined get a coating that is specific to aluminium. Al is very ductile and that is why it galls.
Al loves to be wet, water based coolant is great. Oils will work too, WD-40, tapping oil cutting oil, etc all will work.
You just about can't go too fast in aluminium, but use an RPM that you are comfortable with. Get a squirt bottle with WD-40 and use it to clear your chips when you peck. You can use an acid brush and a can of oil too, when you retract your tool use a wet brush and wipe the chips off.
Good luck.
Yes mostly my work is clamped with a bench vice.
When I use a press, of course I use a clamp. If it isn't practical conventionally I'll use a G clamp. But always clamp.
All the drill I have here are grey/Black oxide, carbide Mills typically for dremel.
If I want accurate deep holes for smaller stuff like 3mm diameter, I have a small collet drill press.
You point about lubrication makes sense, I will try something new.
Rocol tap oil, or 'instant oil' isn't cutting it, so to speak 🤣
Try toilet ring wax, works well in aluminum.
Certain, popular alloys like 6000 series has a tendency to tear and gall easily.
It’s a heat related problem in the end, so keep that in mind.
Certain, popular alloys like 6000 series has a tendency to tear and gall easily.
It’s a heat related problem in the end, so keep that in mind.
6000 is basically pure unalloyed aluminium (which is extremely soft), not a hard alloy - go for hardened alloys if at all possible. Pure aluminium will scratch up horribly and get dented, its not practical for a chassis or box, only for decorative purposes like a mirror effect.
Some aluminium alloys machine better than others, note, look for the phrase "free machining" in the alloy datasheet. Diecast aluminium boxes are the easiest to drill in my experience, but I don't know which alloy they use.
Really soft metals like pure Al and Cu are horrible to machine as they behave more like plasticene than metal, and will stick to the cutter more, have much more friction and jam up tight around the drill risking breakage for deep holes.
As a Mechanical Engineer specializing in materials- a four-digit numerical designation is used to id aluminum and aluminum alloys. Aluminum, 99.0% minimum and greater is classified as 1XXX. Aluminum alloys grouped by major alloying elements magnesium and silicon is classified as 6XXX.
One very commonly used alloy in the USA is 6061, which contains 1.0% Mg, 0.6% Is, 0.2% Cr, and 0.27% Cu.
Reference: Structure and Properties of Engineering Alloys, William F. Smith
One very commonly used alloy in the USA is 6061, which contains 1.0% Mg, 0.6% Is, 0.2% Cr, and 0.27% Cu.
Reference: Structure and Properties of Engineering Alloys, William F. Smith
Phase, interesting, I wondered about something soft like beeswax...thanks.
Interesting also about the drill finish. Typically it's cone drills and step drills that seem to get mangled the worst drilling die-cast ally for example. Peripheral speed I suppose. Admittedly also I am less likely to use a drill press with a cone drill, that's kind of the beauty of them, in some situations, at work at least.
Interesting also about the drill finish. Typically it's cone drills and step drills that seem to get mangled the worst drilling die-cast ally for example. Peripheral speed I suppose. Admittedly also I am less likely to use a drill press with a cone drill, that's kind of the beauty of them, in some situations, at work at least.
No problem!
You’ll find that a double margin bit will allow for better surface finish, especially when not clamped down or by hand held drilling.
You’ll find that a double margin bit will allow for better surface finish, especially when not clamped down or by hand held drilling.
Less pressure - let the bit do the work.
Cutting oil for steel, aluminum seems to like lard for some reason. Beeswax would probably work, but you might have lard (or bacon fat) already and it smells nice when you heat it 🙂
If you keep the bit cool, the metal won't melt to it. Using tools designed for stainless I find makes it easier to chip off the alloy if you need to (usually with your finger nail).
Cutting oil for steel, aluminum seems to like lard for some reason. Beeswax would probably work, but you might have lard (or bacon fat) already and it smells nice when you heat it 🙂
If you keep the bit cool, the metal won't melt to it. Using tools designed for stainless I find makes it easier to chip off the alloy if you need to (usually with your finger nail).
Aluminium and steel require different angles on the cutting edge. A drill or milling cutter design for steel will work poorly in aluminium, and vice-versa.
Consider getting a harder alloy, and look carefully at the temper it is delivered with. It is gummier when soft, so it's often easier to machine something that has been brought to T6.
Some starter reading on tempers.
If you are accidentally buying plate or sheet in 3xxx or 5xxx annealed grade - designed to be press-formed and folded - then that will be horrible to machine. Most sheet and plate are these grades, because a lot of sheet and plate are used for folding and forming, which requires ductility. 6061-T6 just tears if you try to form it, but is good to machine.
Ask your vendor next time what you are actually buying; the different alloys behave very very differently.
Consider getting a harder alloy, and look carefully at the temper it is delivered with. It is gummier when soft, so it's often easier to machine something that has been brought to T6.
Some starter reading on tempers.
If you are accidentally buying plate or sheet in 3xxx or 5xxx annealed grade - designed to be press-formed and folded - then that will be horrible to machine. Most sheet and plate are these grades, because a lot of sheet and plate are used for folding and forming, which requires ductility. 6061-T6 just tears if you try to form it, but is good to machine.
Ask your vendor next time what you are actually buying; the different alloys behave very very differently.
For aluminum, pretty much any thin oil will do the job. A little squirt of WD40, or even kerosene will help a lot to keep it from sticking to steel tooling. As to the file, I'd not try to file aluminum, no matter what lube is used.
Hi,
I tried a suggestion, WD40 the other day and forgot to update (everyone has wd40 right?)
Well, I was impressed at the improvement with WD40, though I hate the smell of the stuff.
IPA worked OK, but WD40 better.
I shall try Meths next!
I tried a suggestion, WD40 the other day and forgot to update (everyone has wd40 right?)
Well, I was impressed at the improvement with WD40, though I hate the smell of the stuff.
IPA worked OK, but WD40 better.
I shall try Meths next!
You hate the smell of WD40? So did my mother. I found that out when I used it to get rid of the squeaking in the furnace fan 🙂 The whole house smelled like it.
Yeah - WD40 smells, and it smokes if you get a lot of heat in your cut. Better is a soluble oil like this:
https://www.huronindustrial.com/fluids/cutting-fluids?product_id=57051&sort=p.model&order=ASC
But as the OP notes - everyone has WD40 around...
https://www.huronindustrial.com/fluids/cutting-fluids?product_id=57051&sort=p.model&order=ASC
But as the OP notes - everyone has WD40 around...